Adding both to the `services` section of your `(operating-system)` form, like
this:
```
(services
(append (list
(service elogind-service-type)
(service seatd-service-type))
%base-services))
```
...will produce this error on running `sudo guix system reconfigure
/etc/config.scm`:
```
guix system: error: service 'file-system-/sys/fs/cgroup' provided more than once
```
...and the command will fail with no further error messages and exit code 1.
Not sure how to figure this out further. Tried `guix system build -K`, `--debug`
and `--verbosity` options; no change in output.
A different config producing the same error message was reported here:
https://www.reddit.com/r/GUIX/comments/14fy6ac/configuration_file_returns_error_when_trying_to/
